http://www.durangobill.com/PowerballOdds.html
Then there's bad Powerball math:
http://www.buzzfeed.com/stephaniemcneal/viral-powerball-hoax
http://www.durangobill.com/PowerballOdds.html
https://www.simonsfoundation.org/uncategorized/new-erdos-paper-solves-egyptian-fraction-problem/#